From the Guidelines
Primary elementary skin lesions are the initial manifestations that arise directly from a disease process, whereas secondary elementary skin lesions result from changes in primary lesions due to disease progression, manipulation, or healing. The distinction between primary and secondary skin lesions is crucial for accurate diagnosis and treatment. Primary skin lesions, such as macules, papules, vesicles, pustules, nodules, wheals, and plaques, appear on previously normal skin and are the direct result of a disease process 1. On the other hand, secondary skin lesions, including scales, crusts, erosions, ulcers, excoriations, fissures, and scars, arise from changes in primary lesions due to various factors 1.
Key Characteristics of Primary and Secondary Skin Lesions
- Primary skin lesions:
- Appear on previously normal skin
- Direct result of a disease process
- Examples: macules, papules, vesicles, pustules, nodules, wheals, and plaques
- Secondary skin lesions:
- Result from changes in primary lesions
- Caused by disease progression, manipulation, or healing
- Examples: scales, crusts, erosions, ulcers, excoriations, fissures, and scars
Understanding the difference between primary and secondary skin lesions is essential for clinicians to determine the chronology and evolution of skin conditions, which is vital for accurate diagnosis and appropriate treatment 1. For instance, recognizing that scales on the scalp are secondary to primary inflammatory papules can help distinguish seborrheic dermatitis from other scaling conditions. In clinical practice, it is essential to consider the origin and development of skin lesions to provide effective treatment and improve patient outcomes.